Geopolymers: raw materials and influence of composition parameters: a review

Abstract

The search for alternative binders to conventional polluting cements has become a necessity given their impact on the environment. One of the solutions lies in the replacement of Portland cements with a new generation of mineral binders, known as geopolymers, which have properties similar to those of Portland cement. These binders are obtained by alkaline activation of siliceous or aluminosilicate materials. This paper summarizes the recently published articles which highlight the different ingredients used in the composition of geopolymer binders: mineral materials serving as alumino-silicate sources and chemical activators used for the synthesis of geopolymers. Parameters influencing the properties of geopolymers such as concentration of the alkaline solution, Si/Al precursor ratio and the curing mode (hardening regime) as well as the hybrid geopolymers, synthesized based on a mixture of two slag/metakaolin aluminosilicate precursors are detailed in the second part. A total of 78 studies were reviewed and discussed.